Showing papers in "Polymer in 1971"

TL;DR: In this article, non-isothermal kinetics of nucleation and its growth are derived by extending Avrami's equation and applied to DSC curves of crystallization obtained by cooling poly(ethylene terephthalate) at constant rates.

TL;DR: In this article, it was shown that double melting peaks in the differential scanning calorimetry (dsc ) and x-ray techniques are due to a recrystallization and melting process taking place while the material is being scanned and not a direct reflection of the state of the material at room temperature prior to the scan.

TL;DR: In this article, the effect of thermal history on the melt distribution observed by differential scanning calorimetry (dsc) and the αγ ratio has been investigated in detail for one copolymer containing 6·5mol% ethylene, and the crystal morphology developed in this copolymers and fractions obtained by solvent extraction is discussed.

TL;DR: In this paper, a theory of the thermodynamic properties of poly(propylene oxide) + carbon tetrachloride and rubber + benzene solutions is outlined. And theoretical equations for applying it to polymer solutions are presented.

TL;DR: In this article, a system of impinging jets has been constructed for the in situ observation of this phenomenon in two simple, analysable flow patterns, corresponding to uniaxial extension and compression.

TL;DR: In this article, the cure of the system bisphenol-a diglycidyl ether/m-phenylene diamine has been monitored by several methods in the range 23-157°C.

TL;DR: In this article, a rubber-modified polystyrene was used to act as a reinforcing agent during microtomy and the effect of sulphur-reinforced poly-(dimethyl phenylene oxide) crazes due to a physical aging process involving polymer flow was investigated.

TL;DR: In this article, the birefringence and mechanical properties of macroscopic single crystals of a three-block copolymer (styrene-butadiene-styrene) are described.

TL;DR: In this paper, a model for a core consisting of a helical array of β-crystallites is shown to give quantitative agreement with the observed x-ray pattern over a wide range of angles.

TL;DR: In this paper, a detailed kinetic analysis suggests that this order results from decreasing rates (in the given order) of self dimerization of the semipinacol radicals.

TL;DR: In this article, new theories of the crystallography of deformation twinning and phase transformations have been used to examine in detail for the first time the crystallographic processes which have been reported to occur in crystalline polyethylene.

TL;DR: In this paper, the authors compared the theory of Flory and experiment results for mixtures of poly(ethylene oxide) and benzene, and attributed the discrepancy between theory and experiment to the occurrence of specific charge-transfer bonding in the mixture.

TL;DR: In this paper, the physical and mechanical properties of linear polyethylene that had been crosslinked under high pressure with various amounts of di-tertiary butyl peroxide were investigated and good correlation was obtained between the amount of peroxide used and the density of the crosslinked polymer.

TL;DR: In this paper, the cationic polymerization of iso butyl vinyl ether initiated by triphenyl methyl and tropylium hexachloroantimonates, and by Triphenylmethyl tetrafluoroborate, has been studied in detail.

TL;DR: In this paper, a series of drawn non-crystalline poly(methyl methacrylate) samples are used to calculate orientation functions, which characterize the molecular orientation, and an excellent correlation exists between the measured birefringence and P 2 ( cos Δ) as expected from the aggregate theory.

TL;DR: In this article, the amplitude and activation energy of β-relaxations were found to be dependent on the water content of the samples and the amount of water absorbed depended on the polarity of the molecule under consideration.

TL;DR: In this article, the size and impact strength of rubber-reinforced polystyrenes were obtained by graft copolymerization using various butadiene polymers and copolymers.

TL;DR: In this paper, a study of the domain morphologies of two block copolymers of the type, (styrene) x (butadiene) y (stylene) x ; for the first sample the molecular weights of the styrene and butadiene blocks were 13 300 and 75 000 respectively, whilst for the second sample they were 10 300 and 71 000 respectively.

TL;DR: In this article, the cationic polymerization of N-vinyl carbazole initiated by tropylium hexachloroantimonate (HX-hexachlorosimonate) and tropyliam perchlorate (Perchlorate) was studied.

TL;DR: In this paper, the molar cyclization equilibrium constants for cyclic phenylmethylsiloxanes, [C 6 H 5 (CH 3 )SiO] x (x = 3-50), have been measured in the undiluted polymer at different temperatures and in solution in toluene.

TL;DR: In this article, a torsion pendulum was constructed to operate inside a thick walled cylindrical pressure vessel, where the pressure medium was nitrogen gas but in some cases the polymer specimen was surrounded with a hydrocarbon oil to prevent the nitrogen from coming into contact with the polymer.

TL;DR: In this article, Lagrange's expansion is applied to the bivariate generating function (trail-weighting generating function) previously introduced for combinatorial calculation in polymer science, and the wide range of applicability of this method is illustrated by calculation of the moments of the molecular weight distribution function, the Stokes radius and the particle scattering factor of random f -functional branched molecules which are monodisperse (i.e. of fixed molecular weight).

TL;DR: In this article, the preparation of comb-shaped polystyrenes by reaction of lithium polystyryl with chloromethylated polystyrene in benzene is described.

TL;DR: In this paper, the properties of polyvinyl trichloracetate (PVtca) cross-linked by polymethyl methacrylate or polystyrene were investigated.

TL;DR: In this paper, a comparison of the dielectric behavior of a normal polyamide (6,10 and 6,6) with poly(sebacyl piperazine), prepared from the secondary diamine piperazines, in which no NH groups are present in the repeat unit is described.

TL;DR: In this article, the Avrami exponent n depends on the crystallization temperature and molecular weight of the fractions and was found to be constant and equal to 4-6 for various fractions, corresponding to spherical and sheaf-like growth from sporadic nucleation.

TL;DR: In this paper, the Avrami equation was shown to be constant and equal to 4 at temperatures of 210-213°C and changed below 210°C, assuming that n = 4, and that the melting point rises with crystallization temperature.